This invention relates generally to face chambers and more particularly to face chambers for use in continuous positive airways pressure treatment.
Patients who suffer respiratory distress are sometimes subjected to a continuous positive airway pressure treatment (CPAP) to assist the spontaneous breathing patient in breathing. This technique maintains a positive pressure (usually 1-30 cm. H.sub.2 O) in the respiratory system at all times. The benefits of positive pressure breathing have been repeatedly documented over the past three (3) decades in the medical literature. This treatment has been administered through an endotracheal tube or by face mask. On one hand, the mask devices available for the administration of positive airway pressure to the individual have certain disadvantages that limit their effectiveness and/or they have poor patient acceptance. On the other hand, the use of an endotracheal tube can effectively provide any desired volume of breathing under any range of pressures, but has a number of serious shortcomings and it creates life-threatening complications in addition to requiring intensive care facilities and expensive respiratory equipment during use.
Examples of this technique are set forth in the following articles:
(1) Gregory, et. al., Treatment of the Idiopathic Respiratory--Distress Syndrome with Continuous Positive Airway Pressure, 284 The New England Journal of Medicine 1333 (1971);
(2) Ahlstrom, et. al., Continuous Positive Airways Pressure Treatment by a Face Chamber in the Idiopathic Respiratory Distress Syndrome, 51 Archives of Disease of Childhood, 13 (1976);
(3) Greenbaum, et. al., Continuous Positive Airway Pressure Without Tracheal Intubation In Spontaneously Breathing Patients, 69 Chest 615 (1976); and
(4) Covelli, et. al., Efficacy of Continuous Positive Airway Pressure Administered By Face Mask, 81 Chest 147 (1982).
In addition to the face masks and chambers set forth in the above articles, the following patents describe various face masks and helmets for other uses which are provided with various ventilation valves and effluent receivers:
______________________________________ U.S. Pat. No. Inventor Issue Date C1/SubC1 ______________________________________ 3,473,165 Gran 10/21/69 3,550,588 Stahl 12/29/70 128/141 3,603,313 Arblaster 09/07/71 128/275 4,249,527 Ko 02/10/81 128/204.18 4,505,310 Schneider 03/19/85 141/114 4,537,189 Vicenzi 08/27/85 128/202.13 4,583,246 Griswold 04/22/86 2/2.1A 4,712,594 Schneider 12/15/87 141/114 ______________________________________
None of the masks or face coverings illustrated in these cited patents are adapted especially for use in CPAP therapy. The face masks or coverings previously used in CPAP therapy were usually uncomfortable, bulky and cumbersome to use and usually required that the patient remain in a restricted environment while such therapy was being performed. Also, in many clinical situations, there are individuals who require more help than that which can be administered with the presently available support equipment short of endotracheal intubation.
The disadvantages of the face masks and devices now readily available for the administration of positive airway pressure are as follows:
(1) The seal of the face mask is incapable of maintaining an air-tight face-to-face interface continuously to provide the airway with a predictable positive pressure;
(2) After placement of the face mask, there is no easy access to the face that will allow the individual to eat, to drink, to swallow medication, to wipe the mouth, to cough and expectorate, to blow or scratch the nose, etc., short of its complete removal. (The performance of such small required or desired functions at times seem insignificant until they are deprived or restricted);
(3) The application of a mask to the face for the purpose of administering continuous positive airway pressure has always been fraught with the danger of aspiration of gastric contents into the lungs, a complication with dire consequences should a person vomit;
(4) A most serious shortcoming is the lack of patient acceptance of the presently available masks due to apprehension since most people perceive them as a means of suffocation rather than aid. (The almost universal reaction of the person is to tear or pull the mask off the face almost immediately); and
(5) With the face mask applied typically over the nose and the mouth, the individual'speech becomes indistinct and difficulty in communication with the patient ensues.
It must be noted here that the introduction of an endotracheal tube into the larynx and trachea immediately deprives the patient of the ability to communicate by speech, literally confines the patient to bed, and requires a special team of nurses and respiratory therapists to provide care for now the patient's:
(1) swallowing has become difficult with the endotracheal tube in place;
(2) the evacuation of his tracheal bronchial secretions must be removed by mechanical suctioning of the endotracheal tube; and
(3) communication is limited to scribbling on a pad, and for those possessing limited writing skills, to banging on the side-rails, etc. The presence of the endotracheal tube also necessitates the use of a nasogastric tube early in the patient's care in order to keep the stomach deflated, to lessen pressure in the left diaphragm, and to prevent aspiration around the cuffed endotracheal tube. Clinically, however, this is not always effective to eliminate aspiration. Besides, it has been shown that the presence of a nasogastric tube causes gastroesophageal reflux with all of its complications to the lower esophagus. Because of the presence of the endotracheal tube in the throat and the tube in the stomach, the person's nutrition and fluid requirements have to be maintained and/or replaced intravenously, and in most instances, by a line placed in a large central vein.
All of the above necessary paraphernalia placed into the patient's orifices and lumina, needless to say, add to one's discomfort and cause anxiety as well as pain and complications. These problems are delineated as follows: (1) aspiration pneumonitis is caused by gastric esophageal reflux; and (2) the suctioning of the tracheal bronchial tube leads to complications of nosocomial infections and/or pneumonia due to Staphylococcus aureus, Pseudomonas aeruginosa or other opportunistic infections. These complications are extremely difficult and costly to treat, may spread to other patients, and, at times, have caused tracheal stricture--a most severe and dreaded life-threatening complication.
The inability of the individual to speak to relatives or those caring for him (i.e., doctors, nurses and other paramedical personnel), as well as the restraining necessary to prevent the patient from forcefully removing the various tubes, leads to often occurring intensive care (ICU) psychosis. More commonly, however, the problem is one of a necessitating heavy sedation that impedes spontaneous breathing and prolongs the use of the respirator. Furthermore, the central intravenous catheter can lead to bacteremia, to lung abscesses, to bacterial endocarditis, and/or to fungal-type blood stream infections in immunosuppressed individuals.
Among the problems not mentioned above is the frequently serious decision of placing an individual whose ability to recuperate is uncertain on the respirator by way of an endotracheal tube. Then, that individual's course becomes protracted and without any foreseeable termination of mechanical respiratory support.